Toroidal type continuously variable transmission

ABSTRACT

A toroidal continuously variable transmission in which a rolling member is arranged between a pair of rotary members with contacting its outer circumferential face with a rolling face of those rotary members being opposed to each other through an oil film, and in which a holding member for holding the rolling member in a rotatable condition is provided includes a lubricating oil feeding hole for spraying lubricating oil to a plurality of portions at the center side of the rotation of at least one of the end faces of the rolling member in an axial direction, which is arranged on the holding member.

TECHNICAL FIELD

This invention relates to a toroidal type (or traction type)continuously variable transmission which is constructed to vary the gearratio continuously by means of varying the torque transmitting pointbetween the rolling member and the rotary member in the radialdirection, with clamping a rolling member between a pair of rotarymembers to transmit a torque from one of the rotary member to the otherrotary member through the rolling member by rotating one of the rotarymember.

BACKGROUND ART

A continuously variable transmission of this kind is constructed with,e.g., clamping a disc-shaped roller between a pair of discs arrangedopposed to each other. The portion of the pair of discs where the outerside from a predetermined radius has an arcuate plane congruent with thearc centered on the center point of opposed planes of those discs, andsuch arcuate plane is leading to circumferential direction. The planethus incurved three-dimensionally is a toroidal plane. The toroidalplane functions as a rolling face and the roller is clampedtherebetween. The roller is a disc-shaped member and its sectionalfigure along in-depth direction of the outer circumferential portion iscongruent with the arcuate figure of the rolling face of the discs.Accordingly, the roller is rotated by means of rotating one of thediscs, and the other disc rotates sequentially. Then, the roller isinclined to move the radial position of the contact portion against oneof the discs, i.e., the radial position from the center axis of the discoutward, and also to move the radial position of the contact portionagainst the other disc to inner circumferential side, so that the speedchange ratio corresponding to the proportion of the radii of eachcontact portions is thereby set.

The amount of the torque to be transmitted by the toroidal typecontinuously variable transmission of this kind is varied in accordancewith the load to clamp the rollers by the discs. The bigger so-calledclamping force of the discs for clamping the roller becomes, the morethe transmittable torque increases pro rata. Also, in the toroidal typecontinuously variable transmission, transmission of the torque isexecuted with forming an oil film between the disc and the roller, andwith utilizing a sharing force of the oil film. Therefore, the biggerthe torque to be transmitted between the disc and the roller is, thebigger the shearing force of the oil film becomes. Accordingly, theamount of heat is increased at the torque transmitting portion.

Generally, a material of above mentioned discs and rollers is a metal,and a treatment to increase surface hardness is applied on those discsand rollers, however, mechanical characteristics of those such ashardness and abrasion resistance is deteriorated if a temperature isrisen when it is under operation due to above mentioned heat generation.In this connection, there is provided a device, which is constructed toexecute cooling with forming an oil film by means of sprayinglubricating oil aggressively to the outer circumferential face of theroller, and feeding the lubricating oil by rotating the roller to theboundary face where the disc and roller are contacted, is disclosed inJapanese Patent Laid-Open 2000-507667 as a prior art. According to theprior art disclosed in the above-mentioned Laid-Open, the oil film maybe formed between the roller and the disc with transporting thelubricating oil blown to the outer circumferential face of the roller tothe contact portion with the disc, by means of rotating the roller.Accordingly, a plenty of lubricating oil contacts with the outercircumferential face of the roller, and cooling of the contact portionbetween the roller and the disc may be thereby executed. However, ingeneral, temperature rise becomes problematic when the roller isrotating in high speed. Accordingly, most of the lubricating oil is easyto be scattered immediately due to centrifugal force even if thelubricating oil is blown to the outer circumferential face of theroller, as disclosed in the above-mentioned Laid-Open. Therefore, amountof the lubricating oil to be fed to the disc is not exactly sufficientand so that there is a disadvantage on the torque transmitting capacityto be limited because of insufficient cooling of the disc.

This invention has been made in the view of the aforementioned technicalproblem, and its object is to provide a toroidal type continuouslyvariable transmission, which has an excellent cooling effect.

DISCLOSURE OF THE INVENTION

In order to achieve the aforementioned objective, the present inventionis characterized by providing a structure for radiating a heat on aportion where is not directory involved in transmitting a torque ataforementioned rotary members such as discs or rollers. Morespecifically, according to the present invention, there is provided atoroidal type continuously variable transmission in which a rollingmember is arranged in between a pair of rotary members with contactingits outer circumferential face with a rolling face of those rotarymembers being opposed to each other through an oil film, and in which aholding member for holding the rolling member in a rotatable conditionis provided therewith, is characterized in that: a lubricating oilfeeding hole for spraying lubricating oil to a plurality of portions atthe center side of the rotation of at least one of the end faces of saidrolling member in an axial direction is provided on said holding member.

According to the present invention, therefore, the rolling membercontacting with the rolling face of the rotary members through the oilface is rotated by means of rotating one of the rotary members, which isclamping the rolling member. Then, the torque is transmitted from therolling member to the other rotary member through the oil film, so thatthe torque is transmitted from one of the rotary member to the otherrotary member after all. In this case, radii of the contact positions ofthe rolling member against each rotary member are differed when therolling member is inclined against the center axis of the rotation ofthe rotary members, and the speed change ratio corresponding to theproportion of the radii is thereby set. And the lubricating oil is blownto the plurality of portions at the center side of the rotation of atleast one of the end faces of the rolling member in the axial directionfrom the feeding hole of the holding member. The lubricating oil flowswith spreading all over the end face by means of the rotation of therolling member, and cools the rolling member with drawing a heat fromthe rolling member in the meantime.

Also, according to the present invention, there is provided acontinuously variable transmission; in which a rolling member isarranged between a pair of rotary members with contacting its outercircumferential face with a rolling face of those rotary members beingopposed to each other through an oil film; in which a holding member forholding the rolling member in a rotatable condition is providedtherewith; and in which the lubricating oil is fed to the rolling memberheld by the holding member in the rotatable condition, is characterizedin that: the holding member comprises a circular plate for covering themost part of at least one of the end face of the rolling member in theaxial direction, with being opposed to said end face.

With this construction, therefore, the speed change ratio is set as thepredetermined value, by means of transmitting the torque from one of therotary member to the other rotary member through the rolling member, andinclining the rolling member against the center axis of rotation of therotary member. The lubricating oil is fed to the rolling member, whereasat least one of the end faces of the rolling member in the axialdirection is covered by the circular plate portion of the holdingmember. Accordingly, the lubricating oil is kept in saturating conditionbetween the rolling member and the rotary member. Consequently, therolling member is cooled by the lubricating oil conserved on the endface side of the rolling member with drawing the heat.

Moreover, according to the present invention, a seal member for formingan oil reservoir between the circular plate portion and the end face ofthe rolling member in the axial direction may be arranged on the outercircumferential portion of the circular plate portion.

With this construction, accordingly, the oil reservoir is formed on theside of at least one of the end faces of the rolling member in the axialdirection, and the rolling member is cooled by the lubricating oilsaturated therein.

Furthermore, according to the present invention, there is provided atoroidal type continuously variable transmission in which a rollingmember is arranged between a pair of rotary members with contacting itsouter circumferential face to a rolling face of those rotary membersbeing opposed to each other through an oil film; and in which a holdingmember for holding the rolling member in a rotatable condition isprovided therewith, is characterized in that: a concavo-convex portionis formed on at least one of the end faces of the rolling member.

The concavo-convex portion may function as a fin for radiating the heat.

With this construction, therefore, the speed change ratio is set as thepredetermined value by means of transmitting the torque from one of therotary member to the other rotary member through the rolling member, andinclining the rolling member against the center axis of rotation of therotary member. Heat radiation from one of the end faces of the rollingmember to the air or to the lubricating oil is expedited by means of theconcavo-convex portion or the fins. As a result, the rolling member isthereby cooled aggressively.

Also, above-mentioned concavo-convex portion may be micro projectionsfor making a flow of the lubricating oil turbulent.

With this construction, accordingly, the flow of the lubricating oilgenerated as a result of the rotation of the rolling member is madeturbulent flow by means of the micro projections. Consequently, heatconductivity from the rolling member to the lubricating oil becomesbigger and the rolling member is therefore cooled aggressively by thelubricating oil.

Still moreover, black body finishing to expedite heat radiation may beapplied to the surface of the rotary member or the rolling member.

With this construction, therefore, heat dissipation from the surface ofthe rotary member or the rolling member is generated aggressively, andas a result, cooling of the rotary member or the rolling member isexpedited, and the temperature rise of those is thereby prevented orsuppressed.

On the other hand, according to the present invention, there is provideda continuously variable transmission; in which a rolling member isarranged between a pair of rotary members with contacting its outercircumferential face with a rolling face of those rotary members shapedinto a full toroidal type curved face being opposed to each otherthrough an oil film; and in which a holding member for holding therolling member in a rotatable condition is provided therewith, ischaracterized in that: fins for radiating the heat are formed on anyportion of the rolling member other than the rolling face.

With this construction, therefore, the speed change ratio is set as thepredetermined value by means of transmitting the torque from one of therotary member to the other rotary member through the rolling member, andinclining the rolling member against the center axis of rotation of therotary member. The rotary member contacts with the lubricating oil orthe ambient air with generating a flowage relatively, by means of itsrotation. In this case, the heat transfer from the rolling member to theambient air or the lubricating oil is expedited by the fins, and as aresult, the rotary member is thereby cooled aggressively.

Still moreover, according to the present invention, there is provided atoroidal type continuously variable transmission; in which a rollingmember is arranged between a pair of rotary members with contacting itsouter circumferential face to a rolling face of those rotary membersbeing opposed to each other through an oil film; and in which a holdingmember for holding the rolling member in a rotatable condition isprovided therewith, is characterized in that: an oil passage for feedingthe lubricating oil to the opposite side of the rolling face of therotary member is provided; and micro projections for making the flow ofthe lubricating oil turbulent are formed on the face to which thelubricating oil is to be fed.

With this construction, therefore, the speed change ratio is set as thepredetermined value by means of transmitting the torque from one of therotary member to the other rotary member through the rolling member, andinclining the rolling member against the center axis of rotation of therotary member. The lubricating oil is fed to the opposite side i.e.,back side of the rolling face of the rotary member, and flown to theouter circumferential side of the rotary member by means of centrifugalforce generated from the rotation. In this case, the flow of thelubricating oil becomes turbulent by the micro projections formed on theback face of the rotary member. As a result, the heat conductivitybetween the rotary member and the lubricating oil becomes bigger, andthe rotary member is thereby cooled aggressively by the lubricating oil.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a drawing showing one example of a power roller in acontinuously variable transmission according to this invention, and (A)is a plane view, (B) is a sectional view;

FIG. 2 is a sectional view showing another example of the power rollerin a continuously variable transmission according to this invention;

FIG. 3 is a side sectional view showing an example of the power rollerwith fins formed thereon which is usable for a continuously variabletransmission according to this invention;

FIG. 4 is a side sectional view showing an example of the power rollerwith micro projections which is usable for a continuously variabletransmission according to this invention;

FIG. 5 is a side sectional view showing an example of a disc with finswhich is usable for a continuously variable transmission according tothis invention;

FIG. 6 is a side view showing an example of a disc with microprojections which is usable for a continuously variable transmissionaccording to this invention;

FIG. 7 is a side sectional view showing an example of a disc in which acover is mounted on its backside;

FIG. 8 is a side sectional view showing an example of an hydraulicchamber formed with mounting a cover on the backside of the disc; and

FIG. 9 is a typical side sectional view showing one example of entireconstruction of a continuously variable transmission according to thisinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

Next, this invention will be described in connection with a specificembodiment shown in the drawings. First of all, to describe one exampleof a toroidal type continuously variable transmission subjected to thisinvention, a double cavity type full toroidal type continuously variabletransmission 1 is depicted typically in FIG. 9. In the toroidal typecontinuously variable transmission 1, a pair of input discs 2 arearranged in so-called back-to-back relation each other, and a pair ofoutput discs 3 are arranged to be opposed to those input discs 2,namely, with sandwiching those input discs 2.

Those discs 2 and 3 are made such that portions of their opposed faceson an outer circumference side from a predetermined radius are shaped,as cut in a plane on the center axis, to have a section of an arcuateplane of a predetermined radius, likewise the discs of the toroidal typecontinuously variable transmission according to the prior art. And apower roller (a rolling member) 4, which corresponds to an idling memberor a transmission member is sandwiched between rolling faces 2B and 3Bwhich are formed into such arcuate plane. That is, the output disc 3 inthe right hand side of FIG. 9 is fixed in the axial direction, and ahydraulic chamber 5 is arranged in the backside (opposite side of therolling face 2B and 3B) of the output disc 3 in the left hand side. Andthe power roller 4 is clamped by each of the input discs 2 and theoutput discs 3 by means of feeding the oil pressure according to thetorque to be transmitted to the hydraulic chamber 5. Namely, it isconstructed to generate the clamping force for clamping the power roller4 by each discs 2 and 3 from the oil pressure to be fed to the hydraulicchamber 5.

Here, each output discs 3 is connected to rotate integrally by an outputshaft 6 arranged along the center axis of those discs, and the outputshaft 6 penetrates center portions of each input discs 2.

Also, a bearing 7 is arranged between each input discs 2 and outputshaft 6, and those input discs 2 and the output shaft 6 are constructedto rotate relatively.

Also, an input shaft 8 is arranged rotatably in parallel with the outputshaft 6. The input shaft 8 is slightly longer than the entire length ofthe continuously variable transmission 1, and gears 9, 10 and 11 areinstalled on three places in total such as its both front and rear endportions, and its intermediate portion. The gear 10 at the intermediateportion is engaged with a gear 12 integrated with said each input discs2. Accordingly, the torque is inputted to the continuously variabletransmission 1 from the input shaft 8 through those gears 10 and 12.

Moreover, said power roller 4 is a disc-shaped member, and the outercircumference of which has a sectional shape formed into a curved facewith the curvature equal to the arc of the rolling face 2B and 3B ofeach discs 2 and 3. The power roller 4 is inclined with respect to theindividual discs 2 and 3; therefore, radial portions of the contactportions between the power roller 4 and the discs 2 and 3 arearbitrarily changed. Three power rollers 4 are arranged between eachinput discs 2 and output discs 3 at even intervals, and six powerrollers are provided all together for the continuously variabletransmission 1 as a whole.

Furthermore, each power roller 4 is held rotatably and inclinably by acarriage 13 which functions as a holding member. This carriage 13 has alubricating oil passage formed for feeding the lubricating oil to theouter circumferential face of the power roller 4, as mentioned below.

Besides, an input gear 14 engaged with the gear 9 installed on the inputshaft 8 is provided, and the input gear 14 is rotated by the motiveenergy of a power source such as an engine (not shown).

One example of the power roller 4 and the carriage 13 is depicted in (A)and (B) of FIG. 1. The carriage 13 shown therein comprises a pair ofcircular plates 131 which has a diameter slightly smaller than the powerroller 4. Two portions of each circular plate 131 opposing each other inthe diametrical parallel are protruded outside of the outer diameter ofthe power roller 4, and formed into butt portions 132 with leading tothe side of the face being opposed to each other. The circular plates131 are assembled integrally with butting the butt portions 132, and asa result, a spaces which is little bit thicker than the power roller 4,is formed between those circular plates 131 to accommodate the powerroller 4 therein. More specifically, the power roller 4 comprises ashaft portion 41 on its center portion, and the shaft portion 41 is heldin a rotatable condition by a bearing 133, which is mounted on thecenter portion of each circular plate 131. Consequently, the powerroller 4 is held by the carriage 13 in a rotatable condition.

A stem 134 as a shaft shaped member is mounted on one of the buttportions 132. This stem 134 is connected with a linear acting typeactuator such as a hydraulic cylinder (not shown) in an oscillatablecondition. The power roller 4, which is clamped by each of discs 2 and 3is moved by the actuator backward and forward, and the power roller 4 isinclined against the center axis of rotation of each discs 2 and 3 inconsequence.

Also, an oil passage 135 is formed along the center axis of the stem134. An end portion of the oil passage 135 of the actuator side iscommunicated with not shown hydraulic feeding unit. And another oilpassage 136 to be communicated with the oil passage 135 is formed ineach circular plate 131. Namely, the oil passage 136 penetrating thecircular plate 131 is formed from one of the butt portion 132 to theother butt portion 132, and the oil passage 136 at each circular plate131 is opened to the butt face.

Accordingly, as shown in FIG. 1, the oil passage 136 at upper and lowercircular plates 131 are communicated each other at the butt portion 132.And the oil passage 135 at the stem 134 is communicated with the oilpassage 136 of the circular plate 131 side in consequence of connectingthe stem 134 with one of the butt portions 132. Besides, the oil passage136 at each circular plate 131 is formed as a loop in order to compassthe outer circumference of each bearing 133. That is, it is constructedto feed the lubricating oil to the bearing 133.

A lubricating oil spraying nozzle 137 to be communicated with the oilpassage 136 is formed on each butt portion 132 with opening to the outercircumferential face of the power roller 4. Also, a plurality oflubricating oil feeding holes 138 for feeding the lubricating oil to theend face of the power roller 4 in the axial direction, i.e., to an upperface and a lower face in FIG. 1 is formed in the vicinity of the centerportion of each circular plate 131 with being communicated with the oilpassage 136 at each circular plate 131. Besides, the lubricating oilfeeding hole 138 may be formed into a plurality of pinhole shaped holes,otherwise, may be formed into narrow slit shape in order to let thelubricating oil spurt in film shape. Accordingly, the lubricating oil isfed to the bearing 133 simultaneously with being spurted to the outercircumferential face and both upper and lower face of the power roller4, by means of feeding the lubricating oil to the oil passage 136 ateach circular plate 131 through the oil passage 135 of the stem 134.

In the aforementioned continuously variable transmission 1, a torque istransmitted to the input disc 2 by means of rotating the input gear 14by not shown power source such as an engine or the like, through thegear 9 engaged with the input gear 14 and the input shaft 8. The powerroller 4 contacting with the rolling face 2B through the oil film isrotated when the input disc 2 rotates, and the output disc 3 is rotatedsubsequently, because the power roller 4 contacts with the rolling face3B of the output disc 3 through the oil film. As a result, the outputshaft 6 integrated with the output disc 3 is therefore rotated.

In this case, the number of revolutions of the power roller 4 isdetermined depending on the number of revolutions of the input disc 2and the radius from the center of rotation at the contact portion withits rolling face 2B. Also, the number of revolutions of the output disc3 is determined depending on the number of revolutions of the powerroller 4 and the radius from the center of rotation at the contactportion of the power roller 4 with the rolling face 3B. Accordingly, thenumber of relative rotations of the output disc 3 to the input disc 2 isdetermined in connection with the radial position of the contactportions of the power roller 4 against each rolling faces 2B and 3B, andspeed change ratio is changed continuously by means of varying thecontact portions of the power roller 4 against each rolling faces 2B and3B by inclining the power roller 4 to the center axis of the outputshaft 6.

The lubricating oil is being fed to the carriage 13 through the oilpassage 135 of the stem 134, when the continuously variable transmission1 is thus under operation. Accordingly, the lubricating oil is fed tothe oil passage 136 of each circular plate 131 with being pressurized,and the lubricating oil is spurt from the lubricating oil sprayingnozzle 137 to the outer circumferential face of the power roller 4 inconsequence. The lubricating oil thus adhered on the circumferentialface of the power roller 4 is transported to the contact portionsagainst each discs 2 and 3 by means of rotation of the power roller 4,and forms an oil film mainly therebetween. And the transmission of thetorque is executed among the power roller 4 and each discs 2 and 3 withutilizing a shearing force of the oil film. Also, a part of thelubricating oil spurt in the power roller 4 is scattered by acentrifugal force, 6 however, the lubricating oil draws a heat form thepower roller 4 and the power roller 4 is thereby cooled.

Also, the lubricating oil fed to the oil passage 136 is spurt from thelubricating oil spraying hole 138 to the portion near the center ofrotation of the power roller 4. The lubricating oil is flown to theouter circumferential side of upper and lower face of the power roller 4by the centrifugal force generated from the rotation, and spread to allover those faces. Especially, in the aforementioned continuouslyvariable transmission 1, both upper and lower face of the power roller 4is covered with the circular plate 131 and it is not the absolute openspace, therefore, the lubricating oil spurt from the lubricating oilfeeding hole 138 is aggressively daubed onto both upper and lower faceof the power roller 4. Consequently, the contacting area between thepower roller 4 and the lubricating oil becomes larger, and the heattransfer from the power roller 4 to the lubricating oil is therebyexpedited. Accordingly, the power roller 4 is cooled aggressively.

Namely, the power roller 4 is cooled efficiently because the lubricatingoil spurt from the lubricating oil feeding hole 138 spreads to bothupper and lower faces of the power roller 4 and draws the heat from thepower roller 4, and because the lubricating oil is thrown off from theouter circumference of the power roller 4 by the centrifugal force.Moreover, the lubricating oil is partially drizzled over the rollingfaces 2B and 3B of each discs 2 and 3, therefore, each discs 2 and 3 iscooled by the lubricating oil with its heat being drawn.

Aforementioned continuously variable transmission 1 is constructed tofeed the lubricating oil to the end face of the power roller 4 in theaxial direction, i.e., the upper face or the lower face in FIG. 1, froma plurality of portions. Therefore, it is possible to feed the filmshaped lubricating oil to the upper face or the lower face of the powerroller 4 entirely with diffusing, as a result, heat conductivity betweenthe power roller 4 and the lubricating oil is thereby improved and thepower roller 4 is cooled efficiently. Moreover, the upper face or thelower face of the power roller 4 is covered with the circular plate 131of the carriage 13; therefore, it is possible to keep the lubricatingoil staying in the upper face side or the lower face side of the powerroller 4. Consequently, the heat conductivity between the power roller 4and the lubricating oil is improved and the power roller 4 is therebycooled efficiently.

As described above, if the lubricating oil is kept in between the powerroller 4 and the circular plate 131, contact between the power roller 4and the circular plate 131 is facilitated the power roller 4 may becooled efficiently. Accordingly, it may also be constructed to form anoil reservoir between the power roller 4 and the carriage 13 in order toconserve the lubricating oil. An example is shown in FIG. 2.

The example shown therein is the example of providing a seal member 139for sealing the space between the circular plate 131 and the powerroller 4 liquid tightly, on the outer circumferential side of thecircular plate 131 opposing to the power roller 4. That is, the sealmember 139 is installed on the carriage 13, and contacts with the upperface or the lower face of the power roller 4 with scraping. Accordingly,the lubricating oil spurt from aforementioned lubricating oil feedinghole 138 flows on the upper face or the lower face of the power roller 4and spreads to the outer circumferential side, however, the oilreservoir is generated on the portion of inner circumferential side fromthe seal member 139, because the flow is arrested by the seal member139. As a result, most part of the power roller 4 is covered with thelubricating oil and its heat is drawn by the lubricating oil, therefore,the power roller 4 may be cooled efficiently.

Besides, if the lubricating oil completely remains in the oil reservoirof inner circumferential side from the seal member 139, a temperaturebecomes higher gradually and no more cooling action is generated.Therefore, in order to avoid such disadvantage, it is preferable togenerate the flowage of the lubricating oil on both upper and lowersides of the power roller 4 with leaking the lubricating oilsequentially by means of forming a notch portion on a portion of theseal member 139, or by means of forming a through hole on the circularplate 131.

Cooling of the power roller 4 is executed with radiating the heat to thelubricating oil or the ambient air as mentioned above, therefore, it ispreferable to form concavo-convex portions on the surface of the powerroller 4 in order to enhance the cooling action. One example of forminga fin 15 for enlarging the heat radiating area is shown in FIG. 3, as anexample of the concavo-convex portions. A plurality of thin fins 15 isformed on both upper and lower faces of the power roller 4 shown in FIG.3. The fins 15 may be formed into a ring shape, a spiral shape, or anappropriate shape arranged at certain intervals such as an arcuateshape.

Aforementioned fins 15 may be held by the carriage 13 which has thecircular plate 131, as shown in FIG. 1 or FIG. 2, because their functionis to enlarge the heat radiating area against the ambient lubricatingoil and air. Otherwise, the power roller 4 shown in FIG. 3 may also beheld by a carriage according to the prior art which is constructed of apair of rectangular plate shaped member, in lieu of the carriage 13.Namely, the amount of the heat radiation by the fins 15 is enhanced andthe power roller 4 may be cooled efficiently, even if in the case ofcooling the power roller 4 with spraying the lubricating oil only to itsouter circumferential face and exposing its both upper and lower face tothe ambient air.

Another example of the concavo-convex portions is shown in FIG. 4. Theexample shown therein is an example of cooling the power roller 4 withthe lubricating oil, and there are formed micro projections 16 formaking a flowage of the lubricating oil turbulent on both upper andlower face of the power roller 4. The micro projections 16 are sawtoothshaped projections as closed up in FIG. 4, such as, a face toward thecenter of the power roller 4 is vertical, and the face leading to theouter circumferential side from the vertical face is an inclined face toform a sectional triangle. Also, the ratio between a pitch p and aheight h (p/h) is set from 7 to 10. Besides, the micro projections 16may be arranged as a circularity formation in the circumferentialdirection, or may be arranged at certain intervals in thecircumferential direction and formed in alternate shifts in the radialdirection.

Also, the micro projections 16 may be formed into regularly arrangedprojections by means of a mechanical processing such as cutting orpressing. Otherwise, the micro projections 16 may be formed intoirregularly arranged projections by means of making surface of the powerroller 4 rough. In this case, the ratio between the pitch and the heightof the micro projections 16 is preferably around 10 to 13 in average.

It is preferable for the power roller 4 in which aforementioned microprojections 16 are formed thereon to be used with being installed on thecarriage 13 having the circular plate 131 as shown in FIGS. 1. or 2.,and the lubricating oil is fed to the portion at the center side of therotation of both upper and lower faces when the torque is transmitted.And the lubricating oil is flown to the outer circumferential side bythe centrifugal force generated from rotation of the power roller 4;however, the flowage of the lubricating oil is made turbulent by meansof the micro projections 16. As a result, heat conductivity between thesurface of the power roller 4 and the lubricating oil becomes bigger,and the amount of the heat to be transmitted from the power roller 4 tothe lubricating oil becomes larger. Therefore, the power roller 4 iscooled efficiently.

In the toroidal type continuously variable transmission 1, as mentionedabove, a heat is generated in consequence of transmission of a torqueamong the discs 2, 3 and the power roller 4, a temperature of the discs2 and 3 which is involved in the transmission of the torque becomesaccordingly higher. If a facial pressure and a temperature of therolling faces 2B and 3B of the discs 2 and 3 become higher, durabilityand abrasion resistance is deteriorated. Therefore, it is desirable tocool the discs 2 and 3 aggressively.

Both of cooling i.e., with the air or with the lubricating oil may beemployed in case of cooling the discs 2 and 3, likewise the cooling ofthe power roller 4 as mentioned above. As shown in FIG. 5, a structurewherein a number of thin plated fins 17 are formed on the back facei.e., opposite side of the rolling faces 2B and 3B may be employed as astructure for executing air-cooling. Besides, it is allowable for thefins 17 to be formed into appropriate shapes such as ring shaped finsleading to the circumferential direction, or into arcuate shaped finesarranged intermittently in the circumferential direction.

Accordingly, the ambient air is flown relatively to the discs 2 and 3when the discs 2 and 3 in which the fins 17 are formed thereon arerotated, and the status becomes compulsory cooling with blowing air tothe fins 17. Consequently, discs 2 and 3 are cooled aggressively by theair from its backside face in connection with the enlargement of theheat radiating area resulted from providing of the fins 17. Therefore, atemperature rise is prevented or suppressed.

On the other hand, a construction for cooling with the lubricating oilis shown in FIG. 6. In the example shown therein, micro projections 18are formed on the backside of the discs 2 and 3. The micro projections18 have a same kind of shape as that of the aforementioned microprojections 16 of the power roller 4 depicted in FIG. 4. A cross sectionin which a face toward the center of the rotation of discs 2 and 3 isvertical and shaped into sawtooth shape, and the ratio between pitch pand height h (p/h) is set from 7 to 10. The micro projections 18 may beformed into regularly arranged projections by means of mechanicalprocessing, otherwise, may be formed into irregularly arrangedprojections by means of chemical treatment for making surface roughnessrough. Moreover, an oil passage 19 for spurting the lubricating oil tobackside of the discs 2 and 3 is formed in an output shaft 6 whichsupports the discs 2 and 3.

According to the construction shown in FIG. 5, the lubricating oil isspurted to the backside of the discs 2 and 3 from the oil passage 19when the discs 2 and 3 is rotated, and then, the lubricating oil isflown to the outer circumferential side by the centrifugal force inconnection with the rotation of the discs 2 and 3. The flowage of thelubricating oil is made turbulent on the surface where the lubricatingoil is to be flown, because there are formed the micro projections 18and surface is like a so-called rough face. Consequently, heatconductivity among the discs 2, 3 and the lubricating oil becomesbigger, and the heat generated as a result of transmission of the torqueis conducted to the lubricating oil aggressively. Accordingly, the discs2 and 3 are thereby cooled.

Besides, the amount of heat transfer between the lubricating oil and thediscs 2, 3 becomes bigger if contacting time of those is long in somelevel. In this connection, for example, it is preferable to make thecontacting time of the lubricating oil and the discs 2, 3 longer in somemeasure, by means of installing a cover 21 which have a through hole 20on its outer circumferential portion with covering the backside of thediscs 2, 3, so as to conserve the lubricating oil spurted from the oilpassage 19 inside of the cover 21, as depicted in FIG. 7. Also, as sownin FIG. 8, a hydraulic chamber 23 may be formed inside of the cover 21,by means of contacting an end portion of inner circumferential side ofthe cover 21 with an outer circumferential face of a flange portion 6Awhich is formed on the output shaft 6.

By the way, heat dissipation is generated in connection with heatradiation (heat emission) other than heat transfer. Therefore, blackbody finishing is applied to at least any one of the surface ofaforementioned discs 2, 3, power roller 4, or carriage 13, in order toincrease its emissivity. An appropriate method such as a heat treatmentor a coating treatment with a ceramic or a resin is sufficient for theblack body finishing. With this construction, the amount of heatdissipation in connection with heat radiation becomes larger inproportion as a temperature rise of the discs 2, 3 or the power roller4, therefore, the temperature rise of the discs 2, 3 and the powerroller 4 may be prevented or suppressed.

Here, this invention should not be limited to the specific embodimentsthus far described, but it may also be applied to a single cavity typefull toroidal type continuously variable transmission, or to a halftoroidal type continuously variable transmission. Moreover, in short, itis sufficient for the fins for executing air cooling to be formed on theportion other than the rolling face, and it is also possible for thefins to be formed on the face of outer circumferential side.

Here will be synthetically described the advantages to be attained bythis invention. According to the present invention, as has beendescribed hereinbefore, the lubricating oil is spurted to a plurality ofportions at the center side of the rotation of at least one of the endface of the rolling member in the axial direction, from the feeding holeof the holding member. The lubricating oil is flown with spreading allover the end face by means of the centrifugal force, and the lubricatingoil cools the rolling member with drawing a heat from the rolling memberin the meantime. Accordingly, a temperature rise of the rolling membersand the rotary members are prevented or suppressed, and as a result, atorque transmitting capacity of the continuously variable transmissionmay be increased, and its durability may also be improved.

Also, according to the present invention, at least one of the end facesof the rolling member in the axial direction is covered with thecircular plate of the holding member and the lubricating oil is keptsaturated therebetween. Therefore, the rolling member is cooled by thelubricating oil conserved on the end face side of the rolling memberwith being drawn the heat. Accordingly, the temperature rise of therolling member and the rotary member are prevented or suppressed. As aresult, a torque transmitting capacity of the continuously variabletransmission may be increased, and its durability may also be improved.

Moreover, according to the present invention, the oil reservoir isformed with the seal member on at least one of the end faces of therolling member in the axial direction and the rolling member is cooledby the lubricating oil saturated therein. Accordingly, the temperaturerise of the rolling member and the rotary member is prevented orsuppressed. As a result, a torque transmitting capacity of thecontinuously variable transmission may be increased, and its durabilitymay also be improved.

Still moreover, according to the present invention, the heat radiationfrom at least one of the end faces of the rolling member in the axialdirection to the air or to the lubricating oil is expedited by the fins,and the rolling member is cooled aggressively as a result. Accordingly,the temperature rise of the rolling member and the rotary member isprevented or suppressed. As a result, a torque transmitting capacity ofthe continuously variable transmission may be increased, and itsdurability may also be improved.

Also, according to the present invention, the flowage of the lubricatingoil at the end face of the rolling member generated from its rotation ismade turbulent by the micro projections. Therefore, the heatconductivity from the rolling member to the lubricating oil becomesbigger, and the rolling member is cooled aggressively by the lubricatingoil. Accordingly, the temperature rise of the rolling member and therotary member is prevented or suppressed. As a result, a torquetransmitting capacity of the continuously variable transmission may beincreased, and its durability may also be improved.

Furthermore, according to the present invention, the black bodyfinishing for expediting the heat radiation is applied to the surface ofthe rolling member or the rotary member, so that the heat radiation isgenerated aggressively from the surface of the rolling member or therotary member. Therefore, the cooling of the rolling member or therotary member is expedited and the temperature rise of those isprevented or suppressed. Also, a torque transmitting capacity of thecontinuously variable transmission may be increased, and its durabilitymay also be improved.

On the other hand, according to the present invention, the rotary membercontacts with the ambient air or the lubricating oil with generating aflowage relatively by means of its rotation. In this case, the heattransfer from the rotary member to the ambient air or the lubricatingoil is expedited by the fins, and as a result, the rotary member isthereby cooled aggressively. Accordingly, the temperature rise of therolling member and the rotary member is prevented or suppressed, so thata torque transmitting capacity of the continuously variable transmissionmay be increased, and its durability may also be improved.

And according to the present invention, the lubricating oil is fed tothe opposite side of the rolling face of the rotary member, i.e., backface of the rotary member, and is flown to the outer circumferentialside by means of the centrifugal force. In this case, the lubricatingoil is made turbulent by the micro projections formed on back face ofthe rotary member, therefore, the heat conductivity between the rotarymember and the lubricating oil becomes bigger and the rotary member iscooled aggressively by the lubricating oil. Accordingly, the temperaturerise of the rolling member and the rotary member is prevented orsuppressed. As a result, a torque transmitting capacity of thecontinuously variable transmission may be increased, and its durabilitymay also be improved.

INDUSTRIAL APPLICABILITY

This invention can be utilized in the field for manufacturing thecontinuously variable transmission and in the field for using thecontinuously variable transmission. Especially, this invention can beutilized in the field relating to an automobile having the continuouslyvariable transmission mounted thereon.

1. A toroidal continuously variable transmission, comprising: a rollingmember rotatable about an axial direction, including an outercircumferential face, and a pair of end faces at opposite ends of therolling member in the axial direction; a pair of rotary members havingrolling faces opposed to each other, the rotary members sandwiching therolling member therebetween, the rolling faces being separated from theouter circumferential face of the rolling member by an oil film; and aholding member that holds the rolling member in a rotatable conditionand including a lubricating oil feeding hole for directly sprayinglubricating oil to a plurality of portions at both of the end faces ofthe rolling member in the axial direction, which is arranged on theholding member, wherein the holding member covers both of the end facesof the rolling member in the axial direction.
 2. The toroidalcontinuously variable transmission according to claim 1, wherein a blackbody finish for expediting heat radiation is applied to a surface of therotary member or the rolling member.
 3. A toroidal continuously variabletransmission, comprising: a rolling member rotatable about an axialdirection, including an outer circumferential face, and a pair of endfaces at opposite ends of the rolling member in the axial direction; apair of rotary members having rolling faces opposed to each other, therotary members sandwiching the rolling member therebetween, wherein therolling faces are separated from the outer circumferential face of therolling member by an oil film; a holding member that holds the rollingmember in a rotatable condition about the axial direction, and in whichlubricating oil is fed to the rolling member at both of the end faces,the holding member including a circular plate for covering most part ofeach end face of the rolling member in the axial direction with beingopposed to the one end face, wherein the holding member covers both ofthe end faces of the rolling member in the axial direction.
 4. Thetoroidal continuously variable transmission according to claim 3,further comprising: a seal member for forming an oil reservoir betweenthe circular plate and the one end face of the rolling member in theaxial direction, which is provided on the outer circumferential portionof the circular plate.
 5. The toroidal continuously variabletransmission according to claim 4, wherein a black body finish forexpediting heat radiation is applied to a surface of the rotary memberor the rolling member.
 6. The toroidal continuously variabletransmission according to claim 3, wherein a black body finish forexpediting heat radiation is applied to a surface of the rotary memberor the rolling member.
 7. A toroidal continuously variable transmission,comprising: a rolling member rotatable about an axial direction,including an outer circumferential face, and a pair of end faces atopposite ends of the rolling member in the axial direction; a pair ofrotary members having rolling faces opposed to each other, the rotarymembers sandwiching the rolling member therebetween, wherein the rollingfaces are separated from the outer circumferential face of the rollingmember by an oil film; and a holding member that holds the rollingmember in a rotatable condition about the axial direction and coversboth of the end faces of the rolling member in the axial direction,wherein a cross section of each end face of the rolling member includesa waveform pattern of microprojections extending circumferentially alongboth the end faces to cause turbulent flow of the lubricating oil; andwherein a cross section of the microprojections is a triangle shapeformed by a vertical face facing a center of the rolling member and aninclined face leading from the vertical face to the outercircumferential side.
 8. The toroidal continuously variable transmissionaccording to claim 7, wherein the waveform pattern of microprojectionsexhibit a sawtooth pattern, each sawtooth extending circumferentially.9. The toroidal continuously variable transmission according to claim 7,wherein a black body finish for expediting a heat radiation is appliedto a surface of the rotary member or the rolling member.
 10. Thetoroidal continuously variable transmission according to claim 7,wherein a ratio between a pitch and a height of the microprojections is7 to
 10. 11. A toroidal continuously variable transmission, comprising:a rolling member rotatable about an axial direction, including an outercircumferential face, a pair of end faces at opposite ends of therolling member in the axial direction, each end face having a crosssection with a waveform pattern of microprojections disposed to extendcircumferentially along both the end faces to cause turbulent flow ofthe lubricating oil; a pair of rotary members having rolling facesopposed to each other, the rotary members sandwiching the rolling membertherebetween, wherein the rolling faces are separated from the outercircumferential face of the rolling member by an oil film; and a holdingmember that holds the rolling member in a rotatable condition about theaxial direction and including an oil passage for feeding the lubricatingoil to the opposite face of the rolling faces of the rotary member.